If it is the push button on a handle then normally the handle needs replacing (approx £5 for a replacement), try a little bit of 3-1 oil first though.
Mike at Agree-a-price frames
September 2010
Automatic Answer
We may have found other answers which could help you.
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix windows and doors.